• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.755-762
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• 2023

The reliability of measuring instruments is essential in measuring cosmic radiation. To demonstrate this importance, this study measured and compared the amount of cosmic radiation using Liulin and TEPC, operated in South Korea, on a flight between Incheon, South Korea and LA, the US. In addition, since prior analysis based on a prediction program is necessary in advance to check the dose of cosmic radiation, this study utilized KREAM developed in Korea and the CARI-6M developed by the FAA to acquire the predicted value. As a result of the verification, the reliability of the two devices falls within the acceptable level of 20%, proving the reliability. Moreover, the differences between the values acquired by each prediction program were only subtle. Nevertheless, the analysis demonstrated that the prediction value obtained by the programs and the measured value had significant differences. Therefore, additional correction of the discrepancies or continuous research for such is required to match the predicted values are similar to the actual measured values.

• Maritime Security
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• v.7 no.1
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• pp.61-96
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• 2023

Amidst the ongoing instability and military tensions between North and South Korea, it is essential for us to comprehend and assess North Korea's military capabilities, while preparing for potential contingencies through military reinforcement. However, to conduct a comprehensive analysis of the military balance on the Korean Peninsula, it is imperative to move beyond simplistic quantitative comparisons of combat capabilities and embrace a broader perspective, which includes qualitative comparisons of military strength, operational capabilities, and a nation's ability to wage war. To address this need, this study employs the method of "Net Assessment" to evaluate the relative combat power of South and North Korean conventional naval forces, with a particular focus on surface combatants. This evaluation involves both quantitative and qualitative comparisons of military assets (personnel and equipment) and intangible factors (naval strategies, geography, etc.). By conducting a holistic assessment, the research aims to identify and analyze strategic asymmetries that may exist between the two navies.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.1
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• pp.43-50
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• 2024

Large planar military antenna boasts a range of electrical components, including TRA(Transmit-Receive Assembly), signal processors, etc. which engage in computations and calculations. These processes generate a significant amount of heat, leading to unforeseen consequences for the equipment. To mitigate these adverse effects, it's imperative to implement a cooling system that can effectively reduce heat-related issues. Given the antenna's intricate nature and the multitude of components it houses, a two-step estimation process is necessary. The first step involves a comprehensive model calculation to determine the total flow characteristics, while the second step entails a thermal analysis of individual TRA set. In this study, we depicted an antenna set using simplified 3D models of its components, considering their material and thermal properties. The sequential analysis process facilitated the calculation of branched flow rates, providing insights into the individual TRA. This approach also allowed us to design a cooling system for the TRA set, assessing its thermal stability in high-temperature environments. To ensure the optimal performance of TRA, breaking down the analysis into stages based on the cooling system's structure can assist operators in predicting numerical results more effectively.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.2
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• pp.156-165
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• 2024

Objectives: This study aims to identify and analyze the exposure status of welding students in specialized high school welding labratories, compare it with the exposure to welding hazards of industrial workers, and seek to improve the educational environment for youth through domestic and international exposure standards. Methods: This study compares the level of exposure to hazardous factors in a welding laboratory of a vocational high school in Jeollanam-do and a welding process in a general industrial site by measuring the work environment. A 10-question survey was conducted to review the effects of welding hazards on the human body, carcinogenicity information, international (US, UK, France) exposure standards, general characteristics between the two groups, and awareness of occupational health. Results: Exposure to hazardous factors in both groups was below the standards set by MOEL. Specialized high school students were exposed to higher levels than workers, and some hazardous factors exceeded the standards when compared to international exposure standards. During the survey, students were less aware of the hazards of welding, safety and health education, and the need for work environment measurement than workers. Conclusions: For the respiratory protection of students in vocational high school welding labs, it is necessary to create a comfortable training environment. Exposure standards for harmful factors should be strictly applied, such as overseas standards, or exposure should be limited by setting a limit on the number of hours of welding practice per week. In addition, it is necessary to conduct safety and health education for welding students to raise their awareness of the importance of measuring the working environment and wearing appropriate protective equipment.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.385-390
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• 2023

The uterus, one of women's reproductive organs, is also closely related to women's health. Among them, hemorrhagic luteal cysts, one of the causes of pelvic pain that women often experience, were observed through CT and ultrasound, and the quality of images was evaluated through quantitative and qualitative evaluations. This study sought to find out whether the test method is more helpful to patients during CT and ultrasound. This study was conducted on 15 adolescent women and 15 adult women(21.31±3.45 average age). The equipment used for filming used EC3-10X (3~10 MHZ) and Philips Mx8000 iCT 256 among Endocavity Probes among Ecube Platinum. After setting a constant ROI on the cyst and the interface as a quantitative analysis method, SNR and CNR values were measured on a 5-point scale based on image quality, lesion clarity, image distortion, clarity of the interface, and motion artifacts (p<0.05). Independent t-test and Mann Whiteny U were performed, and the statistical program used was noted when SPSS (Version 22.0 for windows software package, Chicago, IL, USA) was statistically less than 0.05. Comparing the SNR and CNR values for this experiment, it can be seen that the SNR value was higher in the case of CT images(p<0.05). As a result of the qualitative evaluation, the quality of the image, the clarity of the lesion, the distortion of the image, the clarity of the interface, and the clarity of the boundary were measured on a 5-point scale based on the movement artifact. Comparing each score, CT images scored higher with a finer difference than ultrasound images(p<0.05). In conclusion, both test methods showed excellent results in finding the patient's lesions. However, in quantitative and qualitative evaluations, CT produced higher results in detecting lesions than ultrasound. However, for cyst tests that require continuous observation, ultrasonography, a non-invasive method that is advantageous for patients, will be clinically useful. Therefore, observing the patient's lesions by appropriately distributing these two test methods will provide optimal diagnostic information. These results will be useful for providing clinical basic data and educational materials to CT and US users in the future.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.881-887
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• 2023

This study aims to analyze the development and current trends of AI-based medical imaging devices commercialized in South Korea. As of September 30, 2023, there were a total of 186 AI-based medical devices licensed, certified, and reported to the Korean Ministry of Food and Drug Safety, of which 138 were related to imaging. The study comprehensively examined the yearly approval trends, equipment types, application areas, and key functions from 2018 to 2023. The study found that the number of AI medical devices started from four products in 2018 and grew steadily until 2023, with a sharp increase after 2020. This can be attributed to the interaction between the advancement of AI technology and the increasing demand in the medical field. By equipment, AI medical devices were developed in the order of CT, X-ray, and MR, which reflects the characteristics and clinical importance of the images of each equipment. This study found that the development of AI medical devices for specific areas such as the thorax, cranial nerves, and musculoskeletal system is active, and the main functions are medical image analysis, detection and diagnosis assistance, and image transmission. These results suggest that AI's pattern recognition and data analysis capabilities are playing an important role in the medical imaging field. In addition, this study examined the number of Korean products that have received international certifications, particularly the US FDA and European CE. The results show that many products have been certified by both organizations, indicating that Korean AI medical devices are in line with international standards and are competitive in the global market. By analyzing the impact of AI technology on medical imaging and its potential for development, this study provides important implications for future research and development directions. However, challenges such as regulatory aspects, data quality and accessibility, and clinical validity are also pointed out, requiring continued research and improvement on these issues.

• Geophysics and Geophysical Exploration
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• v.11 no.3
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• pp.167-176
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• 2008

Lau basin of the south Pacific, as an active back arc basin, is promising area bearing seafloor massive hydrothermal deposit that is located in a subduction zone between the Pacific ocean plate and Indo-Australian continental plate. We performed multi-beam bathymetry survey in the Lau basin using EM120, to find out high hydrothermal activity Bone. Fonualei Rift and Spreading Center (FRSC) and Mangatolou Triple Junction (MTJ) area were selected for precise site survey through seafloor morphology investigation. The result of surface and deep-tow magnetometer survey showed that Central Anomaly Magnetization High (CAMH) recorded which is associated with active ridge in FRSC-2 and revealed very low magnetic anomalies that can be connected to past or present high hydrothermal activity in MTJ-1 seamount area. Moreover, the physical and chemical tracers of hydrothermal vent flume, i.e., transmission, hydrogen ion concentration (pH), adenosine triphosphate (ATP), methane (CH4) by use of CTD system, showed significant anomalies in those areas. From positive vent flume results, we could conclude that these areas were or are experiencing very active volcanic activities. The acquired chimney and hydrothermal altered bed rock samples gave us confidence of the existence of massive hydrothermal deposit. Even though not to use visual exploration equipment such as ROV, DTSSS, etc., traditional marine geophysical investigation approach might be a truly cost-effective tool for exploring seafloor hydrothermal massive deposit.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.2
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• pp.71-77
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• 2005

We experienced the specimen that contains a hemoglobin variant known as interference from HbAS in October 2003. It was the first case of Hb variants since Samsung Medical Center began conducting glycohemoglobin College of American Pathologists surveys in 1997. The purpose of this study is to share our experience with the specimen and promote the understanding of Hb variants & derivatives. We've performed cross checks to examine HbA1c by using two pieces of equipment; the TOSHOH G7 and BIO-RAD VARIANT-T(turbo), and Automatic High Performance Liquid Chromatography(HPLC) as an analytic measurement method. HPLC provides different fractional information of hemoglobin with a two-dimensional graph as well as numeric results. We have been performing a "Systematic Checking Process". Three specimen suspicious of Hb variants & derivatives were found through this process. College of American Pathologists notified that it is important for users to be aware of the limitation of their glycohemoglobin method to avoid reporting incorrect results due to interference from hemoglobin variants or hemoglobin adducts. Therefore, laboratory findings of Hb variants & derivatives are very important. The experience of qualified technicians with professional knowledge in Hb variants is the most important aspect in finding Hb variants. Korea is homogeneous in race and is not in an area with a higher finding rate of Hb variants. While 1,024 cases of Hb variants have been found in Japan, we do not have specific data on how many cases of Hb variants have been found in Korea. Considering Hb variant cases in Japan, which is geographically close to us, it is presumed that there must be various Hb variant cases in Korea. If domestic laboratories set a systemic protocol and build a network to share our experience in Hb variants, I expect the Korean Hb variants could also be listed on the world's Hb variant list.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.295-305
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• 2011

In this study, a seismic behavior of electrical cabinet system in Nuclear Power Plants(NPPs) was evaluated by the shaking table test. A 480V Motor Control Centers(MCCs) was selected for the shaking table test, and a real MCC cabinet for the Korea Nuclear Power Plant site was rented by manufactured company. For the shaking table tests, three kinds of seismic input motions were used, which were a US NRC Reg. guide 1.60 design spectrum, a UHS spectrum and PAB 165' floor response spectrum(FRS). Especially, the UHS input motion was selected for an evaluation of structural seismic amplification effects, three directional accelerations were measured at three points outside on the cabinet system and also that of the incabinet response amplification, accelerations were measure at two points which were mounted in electrical equipment such as relay. Seismic amplification effect is determined at the outside and inside of a cabinet as input seismic motion, and compared to the results which are calculated by analytical method based on NUREG/CR-5203.

• Fire Science and Engineering
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• v.33 no.6
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• pp.105-113
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• 2019

This study investigates the toxicity characteristics of two Non-Class 1E Cables (For security reasons, we refer to company A and company B) used in nuclear power plants according to the accelerated deterioration period. In accordance with NES 713 test equipment and standards, tests were carried out on non-aged cables and the cables subjected to 20- and 40-year-accelerated-deterioration; each of the cables was further classified into sheath and insulation. The test results showed that the toxicity indices of 20- and 40-year-accelerated-aged cables were higher than those for the non-aged cables, and 20-year-aged cables of both A and B companies showed the highest toxicity indices. This is attributed to the extensive emissions of carbon monoxide and halide gases such as hydrogen chloride and hydrogen bromide. Furthermore, to analyze the toxicity indices of sheath and insulation in detail, the US Department of Defense standard (MIL-DTL) was applied to determine whether the Toxicity index (T.I.) allowance was exceeded, and the results showed that the insulating materials emitted considerably more than the allowable limit.